Democracy works, but not for the reasons one might expect, psychologist and author Danny Oppenheimer asserted Thursday during a morning convocation.

It’s not informed decision-making of voters that drives a democracy to succeed, said Mr. Oppenheimer, co-author of this year’s all-school read, Democracy Despite Itself. In fact, Mr. Oppenheimer and others have discovered that voters decide whom to elect based largely on irrational influences, faulty memories, and seemingly irrelevant factors.

Instead, he explained, it’s the mere fact that citizens can vote at all that keeps democracies moving forward, producing healthier, more educated, longer-lasting, more successful societies than non-democracies do. When people feel they are participating in a fair system, they tend to follow the rules and support a stable society. When they feel they don’t have a voice or believe the system is unjust, he said, they tend to refuse to cooperate, breaking down society, as happened with the Arab Spring last year.

Mr. Oppenheimer and co-author Mike Edwards spent Thursday on campus as part of the Hubbard Speaker Series. After the convocation, they held a question-and-answer session with students and faculty and visited afternoon classes, and in the evening they were to lead a discussion and book signing for the wider community in Gilchrist Auditorium. The authors’ visit is part of a larger examination of democracy as Loomis Chaffee’s school theme this year.

At the convocation, Mr. Oppenheimer demonstrated some of the myriad influences on voters’ decision-making, few of which relate to candidates’ ideology or proposed policies.

In one study he conducted with a colleague, he said, subjects answered a political attitudes survey while seated randomly in chairs that tilted to the left or the right. People whose chairs tilted to the left were 15 percent more liberal in the survey, and people whose chairs tilted right were almost 9 percent more conservative. “Left-leaning” and “right-leaning” seemed to take a literal meaning and make it figurative.

In other examples that set the audience abuzz, Mr. Oppenheimer showed the power of a visual message over a contradictory audio message, demonstrated the ease with which a person can remember things incorrectly, and revealed people’s natural tendency to try to confirm their hypotheses rather than trying to disprove them. In other words, faulty information can form the basis of voters’ decisions.

“The human mind is not designed for politics,” Mr. Oppenheimer concluded. Yet, democracies succeed and thrive by many different measures. As the book details, the perception of fairness and justice in a democracy makes a society run more smoothly than a system that gives no voice to a large segment of its population. He warned that the ongoing debate over voter identification laws undermines people’s sense of fairness no matter which side of the issue they support. Voter ID laws themselves would make no difference in the outcome of any large election, he said, but the perception of lack of fairness — either with or without a voter ID law in place — is bad for democracy.

As for the upcoming presidential election, Mr. Oppenheimer opined, somewhat tongue-in-cheek, that Governor Romney’s height and “awesome hair” and President Obama’s ability to pick college basketball game winners cancel each other out in their cachet with voters. But he predicted that President Obama would win re-election because Governor Romney’s occasional gaffes fit into neat sound bites that hurt his image with undecided voters.